For questions 2 and 3. It is known that the mean diameter of pine trees in a national forest is 9.6 (inches) with a standard deviation 2.4 (inches). Assuming that the tree diameters are distributed normally. If a pine tree is to be selected randomly from this forest, what is the probability that its diameter will fall between 7.2 inches and 14.4 inches?

0.8185

Step-by-step explanation:

Let X represents the tree diameters that are distributed normally.

Given: Mean , Standard deviation  

The probability that its diameter will fall between 7.2 inches and 14.4 inches will be:

Hence, required probability = 0.8185

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.